Answers for "belongs_to with foreign key laravel"

laravel foreign key constraint

public function up()
{
    Schema::create('replies', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->text('body');
        $table->unsignedBigInteger('question_id');
        $table->integer('user_id')->unsigned();
        $table->foreign('question_id')->references('id')->on('questions')->onDelete('cascade');
        $table->timestamps();
    });
}

Laravel adding Foreign Key Constraints

$table->foreignId('user_id')
      ->constrained("users") <- // You don't need to specify table if it matched laravel naming conventions.
      ->onUpdate('cascade')
      ->onDelete('cascade');